限流值可调的双门限限流保护电路设计

Design on double threshold current limiting protection circuit with adjustable current limiting value

为了有效提高限流保护电路在不同场合中的工作效率,设计了一种宽范围限流值的双门限限流保护电路应用于电源管理。通过采样管采样输出电流,保证了限流值的精度;引入限流值设置电路,通过调整外接电阻阻值,改变限流环路的参考电流,从而实现限流值的宽范围输出。在输出端短路情况下,所设计的电路通过开关控制电流采样比例,可将短路限流值降低为预设值的3/4。该电路采用0.18μm工艺实现,Cadence仿真表明,设计电路各项参数指标达到设计要求,有较大的实际应用价值。

In order to effectively improve the efficiency of the current limiting protection circuit in different occasions,we designed a double threshold current limiting protection circuit with wide range current limiting value,which could be applied to power management chip.The output current was sampled by the sampling tube to ensure the accuracy of the current limit value.The current limiting value setting circuit was introduced to change the reference current of the current limiting loop by adjusting the external resistance value,so as to realize the wide range output of the current limiting value.In the case of short circuit at the output,the short-circuit current limit could be reduced to 3/4 of the preset value by controlling the current sampling proportion through the switch.The circuit was fabricated with a 0.18μm technology.The simulation verification by Cadence simulation software shows that each parameter index of the designed circuit meets the design requirements and has great practical application value.